A transmitter of a 3GPP LTE system performs channel encoding, rate matching, and interleaving processes on an information source, and a receiver of a mobile communication system performs derate matching, deinterleaving, and channel decoding processes.
The rate matching process is done for matching the number of encoded bits with a maximum traffic of a channel by performing repetition or pruning according to a rate matching pattern prior to transmission of the number of encoded bits over a channel. The interleaving process is done for rearranging the order of an encoded bit stream in order to recover an original bit stream, even though some bits of the bit stream are lost by instantaneous noise.
The derate matching process is done for releasing the rate-matched state of the received data prior to decoding of the received data repeated or pruned at the receiver of the mobile communication system. The deinterleaving process is done for rearranging the interleaved bit stream in the original order.
FIG. 1 is a block diagram of a related art receiver of a mobile communication system which performs a derate matching process and a deinterleaving process.
Referring to FIG. 1, the related art receiver 10 includes an input data separating unit 11, a derate matching processing unit 13, a derate-matched data storing unit 15, a deinterleaving processing unit 17, and a deinterleaved data storing unit 19.
The input data separator 11 separates input data from a signal transmitted from a transmitter over a channel.
The derate matching processing unit 13 performs a derate matching process to accumulate data bits with respect to data bits of the repetition input data, determine the accumulated input bits as a final data, and insert “0” into data bit positions of removed data with respect to the data bits of the pruned input data.
The derate-matched data storing unit 15 stores the derate-matched data.
The deinterleaving processing unit 17 deinterleaves the derate-matched data stored in the derate-matched data storing unit 15.
The deinterleaved data storing unit 19 stores the deinterleaved data.
As such, the general receiver of the communication system which performs the derate matching process and the deinterleaving process requires two memories which store the derate-matched data and the deinterleaved data.
Furthermore, a total data processing time necessary to recover the original data corresponds to a processing time of the derate matching process and a processing time of the deinterleaving process.
Meanwhile, a communication system such as a 3GPP LTE system includes a packet data channel for data transmission, and a packet data control channel for efficient data transmission. The data are transmitted over the data channel. The data transmission through air is performed on the basis of a physical layer packet (PLP), and the length of the physical layer packet varies at every transmission.
Control information data required to enable the receiver to receive data efficiently are transmitted over the data control channel. Therefore, the receiver performs the derate matching process and the deinterleaving process on the data and the control information data separately.
In particular, when derate matching the control information data, the derate matching process must be completed within a processing time required by the receiver. However, the derate matching process on the control information data is performed up to 60 times. Thus, the time necessary for the derate matching process becomes long. A method of implementing a plurality of derate matching processing units at the receiver may be taken into consideration, but its hardware implementation is difficult.